Pneumatic filing device



Sept. 9, 1941. H. B. SPINK PNEUMATIC FILING DEVICE- Filed Jan. 24, 1940 2 sheets-sheet 1 ATTORNEY l 1941- H. B. SPINK 2,255,395

PNEUMATIC FILING DEVICE Filed Jan. 24, 1940 2 Sheets-Sheet 2 'IIIIIIIIIIIIAfIIIII/III"Illfl IIIIIIII I/IIIIIIIII IIIIIIII/IIIIIIII/IIIJ WIII/IIIJ allllllllllllillllllll INVENTOR fiiwda ATTORNEY Patented Sept. 9, 1941 UNITEDSTATES PATENT OFFICE PNEUMATIC FILING DEVICE Harry Burdette Spink, West Palm Beach, Fla.

Application January 24, 1940, Serial No. 315,343

4 Claims.

This invention relates to improvements in portable power tools for metal trimming and like use and consists of an improved pneumatically operated device particularly adapted for reciprocating an abrasive or cutting tool such as a rasp or file so as to facilitate the operation of metal trimming or finishing.

A particular object of the present invention is to provide a portable tool of light weight, good balance and conveniently operable design which will be well suited for manual direction or manipulation and control and wherein the power reciprocation of the working tool will materially expedite the operation thereby resulting in increased efliciency and labor economy, particularly in operations such as automobile body work, fender trimming and like operations wherein shifting of the operating position is a factor.

To this end I have designed a pneumatically actuated tool reciprocating device employing an axial bearing member supporting a stationary piston upon which is slidably mounted a movable cylinder carrying a suitable tool holder and having automatically actuated valve means to effect the reciprocation of the cylinder and tool carried thereby; the assembly including a desirable arrangement of manual support and valve control features contributing materially to the facility of operation and improved balance of the tool. In addition, there is provided supplemental valve means for controlling the maximum power fluid or air intake to the device to govern the maximum speed of operation.

The described and other features and advantages of the present invention will be more fully understood by reference to the accompanying drawings wherein like reference characters are applied to the corresponding parts in the several views.

In the drawings:

Fig. 1 is a view of my improved device taken in side elevation.

Fig. 2 is a vertical, sectional view thereof taken centrally and longitudinally thereof.

Fig. 3 is a vertical, cross-section taken on line 3-4 of Fi 2.

Fig. 4 is a detail, cross-section of the piston and valve structure taken on line 44 of Fig. 2.

Fig. 5 is a similar view taken on line 5-5 of Fig. 2. y

Fig. 6 is a detail, longitudinal, sectional view of the same taken on line 6-8 of Fig. 2.

Figs. 7 and 8 are diagrammatic, sectional views of the valve and piston port arrangement showing the valves respectively in reversed position and indicating with arrows the intake and exhaust of the operating fluid.

In the approved embodiment of the features of my invention as here shown, the device comprises a rigid or stationary assembly of supporting parts including an elongated bearing tube 2 to which is attached at one end a valve member 3 and handle bracket 4, the upper end -of the latter being connected by hearing rod 5 to a forward bracket 6 connected to the opposite or forward-end of the bearing tube 2. Also rigidly connected therewith there is a protective casing member 8 having a forward hand grip 9 on its upper, forward portion. The valve member is threaded to receive the forward threaded portion of the tube 2. The bracket 4 and easing 8 are fitted over the tube and clamped against the member 3 by nut lil. At the opposite end the bracket 6 and the casing are fitted over the tube 2 and rod 5 and clamped by the nuts l2-l3 and the rod 5 at its rearward end is secured by threading to bracket 4 secured by lock nut 14. The rod 5, as shown, is of angular form, having a forward bearing guide portion IS in parallel relation to the tube 2.

Upon the bearing tube 2 there is fixedly supported a stationary piston member l8 which is enclosed within a movable cylinder l9 closely fitted thereto with the usual interposed piston rings and supported at its ends by end wall bearing members 20--2l or glands fitted to be slidable upon the tube 2. The members 20-2l as shown are provided with threaded bearing collars 22-23 and suitable packing 24. The forward cylinder end wall member 20 is upwardly extended and formed with a bearing aperture 28 slidable upon the rod portion IS. The members 20 and 2| are formed with spaced downward extensions 28 apertured to support pins 30 passed through angularly formed tool supports 3| having upper forked lug portions 32 and lower flange portions to which is secured a flexible backing plate 34 for a cutting tool, here shown. as a file 36, secured at its forward end by clamping screw 38 and nut 39 and at its rearward end by clamping screw 40; the screws 38 and 40 being headed and fitted to countersunk apertures in the file body. The pivotal mounting of the tool supports 3! permits of flexing the files to either convex or concave curvature by means of ad justing parts consisting of a threaded rod 42 pivotally secured to the rearward support 3| and engaged at its forward end by internally threaded adjusting collar 43 rotatably secured to forward member 3| by being formed with an anof the member II.

To reciprocate the cylinder and tool under fluid pressure, the valve member 3 is formed with a threaded portion 45 adapted for the attachment thereto of the air line from a suitable compressor and has a longitudinal passage or duct 46 communicating through an intake tube 41 connected at its inner end to an intake port 48 of the piston is. The admission of the operating fluid is controlled by the retractive needle valve I pivotally connected by link 52 to a pivoted trigger control lever 54 supported on pin 55 carried by bracket 4. The valve 50 is normally closed under the influence of spring 58 connected to pin 51 and the trigger arm as shown. A supplemental threaded needle type valve 59 is also provided to adjust the maximum operating pressures as may .be desired.

As will be best understood by reference to Figs. 6, 7 and 8, the reciprocal movement of the cylinder under the action of the fluid pressure is effected under the control of valve slides or slide valve members carried by the piston and shifted into reverse operating position in effect by engagement therewith of the cylinder end walls at the end of each stroke. The slide valve members,

t comprise the intake control valve slide 80 and the exhaust control valve slide 62 which, structurally, are arranged as shown in Figs. 4 and 5, extending longitudinally through the piston by fitting suitable bores therein and are of a length to extend beyond the piston body-to either side thereof. The intake slide 60, as best understood by reference to diagrammatic, sectional views of Figs. 7 and 8, is formed with inner ports 63 and 63', each communicating with the cylinder interior at its side of the piston by passages or bores 8464' and positioned so as alternately to register with the port 48 of tube 41 through a small connecting bore in the piston. Accordingly when shifted axially of the piston the intake valve slide will operate to admit the operating fluid to one and then to the other side of the piston.

In similar manner, the exhaust valve slide 62, is provided with inner ports 6668 communieating with bores 68-68 opening into the cylinder at opposite sides of the piston. The ports 66-66 are positioned alternately to register with coacting exhaust ports formed in the piston and tube 2; as shown exhaust port I0 cooperating with port 86. The valve slides 6|! and 62, as shown, in Fig. 6, are connected to move in unison by being formed integrally with an end connecting wall 14. To yieldingly retain the valve slides in the positions of port registration at the end of the its stroke, the valve member 62 is formed with recesses engaged by spring pressed ball I6 operating within a bore in the piston as shown.

In operation, under the fluid pressure, the cylinder is carrying the cutting tool or flle will be reclprocated axially on the bearing tube 2 and at the end of its stroke, the end walls of the cylinder, through the intermediary of buffer coil springs 80 secured to the end walls -2l and valve slide members 60-62 will shift the valve slides to effect reversal of the cylinder stroke. This valve operation will be best understood by reference to Figs. '7 and 8 wherein the respective operating positions of the valve slides is shown. As shown in Fig. 7 and as indicated by arrows, the port registration is such as to admit intake of the surrounding the tube, by engagement with the 2,255,896 nular groove 44 fitted between the forked lugs operating fluid to the cylinder at the left or forward of the piston to effect movement of the 0371- inder in that direction while at the same time the exhaust ports communicating with the opposite side of the piston are open or in registration. In Fig. 8 is shown, the oppositely shifted position of the valve slides and reversal of the port registration operative for admission of fluid to the right or rearward side-of the piston as indicated. The exhaust as will be understood passes I iciiultivsirdiy through the forward open end of the The arrangement of the hand grips, as shown, above and forwardly and rearwardly positioned of the device produces a desirable balance and instinctive alignment for improved operation and accurate guidance by the operator. As will be understood, the trigger valve in the arrangement as shown provides for convenient and responsive control of the air intake contributing to the facility of the trimming or flling operation with my improved device.

Having described my invention, I claim:

1. A fluid operated tool reciprocating deviceof the character described comprising a longitudinally extending bearing member, forward and rearward brackets on the bearing member upwardly extending therefrom, a bearing rod connecting the upper portions of the brackets and formed with a forward bearing portion parallel to the bearing member and having an upwardly inclined rearward portion connected to the rearward bracket, a piston secured on the bearing member, a cylinder slidably bearing on the bearing member and having an upward extension having slidable engagement with the bearing rod, a tool holder supported by the cylinder member at the underside thereof, means for admitting and exhausting operating fluid at opposite sides of the piston including an intake pipe and a manually controlled valve in the intake pipe.

2. A fluid operated tool reciprocating device of the character described comprising a longitudinally extending bearing member, forward and rearward brackets on the bearing member upwardly extending therefrom, a bearing rod connecting the upper portions of. the brackets and having a bearing portion parallel to the bearing member and having an upwardly inclined rearward portion connected to the rearward bracket, a piston secured on the bearing member, a cylinder slidably bearing on the bearing member and having an upward extension fitted for sliding engagement with the bearing rod, a tool holder supported by the cylinder member at the underside thereof, means for admitting and exhausing operating fluid at opposite sides of the piston to reciprocate the cylinder including an intake pipe, a manually controlled valve in the intake pipe, a control trigger therefor pivotally supported on the rearward bracket and a connection therefrom to the manually controlled valve.

3. A fluid operated tool reciprocating device comprising, a longitudinally extending bearing tube, a piston element aflixed to the tube and formed with an intake port, a cylinder mem ber enclosing the piston and slidably bearing on the tube, a tool holder carried by the cylinder member to the underside thereof, intake and exhaust valve slides fitted to the piston for controlling the admission and exhaust of operating fluid at opposite sides of the piston, buffer springs fltted to surround the bearing tube within the cylinder end portions, said valve slides being shiftable by engagement with said buffer springs, yieldable retaining means engaging the valve slides, said piston having intake and exhaust ports for cooperating with the valve slides, an intake pipe connecting with the intake port of the piston and a manually controlled valve in the intake pipe.

4. A fluid operated tool reciprocating device comprising a longitudinally extending bearing tube, a piston element affixed to the tubeand formed with an intake port, a cylinder member enclosing the piston and slidably bearing upon the tube, a tool holder carried by the cylinder member, intake and exhaust valve slides fitted to the piston to be movable axial thereof, buffer springs within the cylinder ends positioned to engage the valve slides, yieldable retaining means carried by the piston engaging the valve slides to retain them in their respective positions, said piston having intake and exhaust ports cooperatively related to the valve slides, an intake pipe connecting with the piston intake port, forward and rearward supporting grips for the device positioned above the bearing tube, a control trigger lever pivotally supported with relation to the rearward grip, a control valve in the intake pipe and a connection from the control trigger thereto, substantially as described.

" HARRY B. SPINK. 

